This invention relates to apparatus for forming plies of material such as textile fabric or the like, and more particularly to apparatus for sewing plies of material together with controlled loading and guidance of the plies.
In one respect, the invention involves improvements upon the Apparatus for Seaming Pieces of Textile Fabric or the Like of my prior U.S. Pat. No. 3,867,889, issued Feb. 25, 1975. In said prior patent, there is disclosed an earlier apparatus of my invention for sewing two pieces or plies of material with the start and finish ends of the plies sewed out even and matching, and in which the starting ends of the two plies are matched and any out-of-registration condition of the trailing ends of the plies as they are fed through the sewing machine is sensed and the relative speed of feed of the two plies through the sewing machine varied in accordance with this sensing to bring the trailing ends of the plies substantially into registration. Thus, if the upper of the two plies is longer than the lower, the apparatus senses this and increases the rate of feed of the upper ply relative to the lower ply to cause the trailing ends of the plies to come out even, taken up the excess in the length of the upper ply in effect by puckering up the upper ply.
While my said prior apparatus is quite satisfactory insofar as seam end equalization is concerned for many applications, its production rate may be lower than desired for some operations due to the fact that the loading of an item of work (e.g., a pair of plies) into the apparatus generally cannot be started until the preceding item has been completely sewn, meaning that the sewing time per item is idle time insofar as loading is concerned.